Encoding and Decoding Architectures for Format Compatible 3D Video Delivery

ABSTRACT

Encoding and decoding architectures for 3D video delivery are described, such as 2D compatible 3D video delivery and frame compatible 3D video delivery. The architectures include pre-processing stages to pre-process the output of a base layer video encoder and/or decoder and input the pre-processed output into an enhancement layer video encoder and/or decoder of one or more enhancement layers. Multiplexing methods of how to combine the base and enhancement layer videos are also described.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/376,707, filed on Dec. 7, 2011, which is the national phasestage of International Patent Application No. PCT/US2010/040545, filedon Jun. 30, 2010, which claims the benefit of priority to U.S.Provisional Application No. 61/223,027, filed on Jul. 4, 2009, each ofwhich is incorporated herewith by reference in its entirety.

FIELD

This disclosure relates to image processing and video compression. Moreparticularly, embodiments of the present disclosure relate to encodingand decoding systems and methods for 3D video delivery, such as 2Dcompatible and frame compatible 3D video delivery.

BACKGROUND

The provision of a stereoscopic (3D) user experience is a long held goalof both content providers and display manufacturers. Recently, theurgency of providing a stereoscopic experience to home users hasincreased with the production and tentative release of multiple 3Dmovies or other 3D material (e.g., concerts or documentaries).

To ensure rapid adoption among consumers, the ideal solutions should bethose that can be implemented with minimal or no alteration to existingplayback devices such as set-top boxes, DVD, and Blu-ray disc players,as well as existing 3D capable displays, such as digital lightprocessing (DLP) displays by Samsung and Mitsubishi, some Plasmadisplays, and polarized based and frame sequential LCD displays.

One possible method for the delivery of 3D content that has theseproperties is the consideration of creating, coding, and delivering 3Dvideo content by multiplexing the two views into a single frameconfiguration using a variety of filtering, sampling, and arrangementmethods. Sampling could, for example, be horizontal, vertical, orquincunx, while an offset, e.g. a sampling offset, could also beconsidered between the two views allowing better exploitation ofredundancies that may exist between the two views.

Similarly, arrangements could include side by side, over-under,line-interleaved, and checkerboard packing among others, as shown inFIGS. 1-6. Unfortunately, these methods do not provision for thedelivery of full resolution stereoscopic material, which can impactquality and experience, and essentially can be an issue for manyapplications.

The desire for full resolution has lead to some systems that utilize twoseparate and independent bitstreams, each one representing a differentview, like the simulcast 3D video delivery architecture shown in FIG. 8.Unfortunately, the complexity of this method, its bandwidthrequirements, i.e. redundancies between the two views are not exploited,but also the fact that this method is not backwards compatible withlegacy devices and can have considerable implications to the entiredelivery system, has not lead to its adoption.

An extension of this method, that tries to exploit some of theredundancies that may exist between the two views was proposed andadopted as a profile of the Multiview Video Coding (MVC) extension ofthe MPEG-4 AVC/H.264 video coding standard, i.e. the Stereo Highprofile, that provisions for the encoding and delivery of stereoscopicmaterial. An example of the MVC based 3D video delivery architecture isshown in FIG. 9. Redundancies are exploited using only translationalmotion compensation based methods, while the system is based on“intelligent” reference buffer management, i.e. in which orderreferences from the base or enhancement layers are added in theenhancement layer buffer and considered for prediction, for performingprediction compared to the original design of MPEG-4 AVC. Unfortunately,even though coding efficiency was somewhat improved (i.e., 20-30% oversimulcast), complexity issues, incompatibility with legacy devices (only2D support is provided), and the not so significant performance benefitspresented using such method still make it as a somewhat unattractivesolution.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate one or more embodiments of thepresent disclosure and, together with the description of exampleembodiments, serve to explain the principles and implementations of thedisclosure.

FIG. 1 shows a checkerboard interleaved arrangement for the delivery ofstereoscopic material.

FIG. 2 shows a horizontal sampling/column interleaved arrangement forthe delivery of stereoscopic material.

FIG. 3 shows a vertical sampling/row interleaved arrangement for thedelivery of stereoscopic material.

FIG. 4 shows a horizontal sampling/side by side arrangement for thedelivery of stereoscopic material.

FIG. 5 shows a vertical sampling/over-under arrangement for the deliveryof stereoscopic material.

FIG. 6 shows a quincunx sampling/side by side arrangement for thedelivery of stereoscopic material.

FIG. 7 shows a frame compatible 3D video delivery architecture.

FIG. 8 shows a simulcast 3D video delivery architecture.

FIG. 9 shows an MVC based 3D video delivery architecture.

FIG. 10 shows an example of 3D capture.

FIG. 11 shows pre-processing stages located between a base layer and anenhancement layer, and between a first enhancement layer and a secondenhancement layer of a frame compatible 3D architecture.

FIG. 12 shows pre-processing stages located between the base layer andthe enhancement layer of the video encoder, and the base layer and theenhancement layer of the video decoder of a 2D compatible 3Darchitecture, in accordance with the present disclosure.

FIG. 13 shows a more detailed diagram of the pre-processing stage ofFIG. 12 on the encoder side.

FIG. 14 shows a more detailed diagram of the pre-processing stage ofFIG. 11 on the encoder side.

FIG. 15 shows a more detailed diagram of the pre-processing stage ofFIG. 11 on the decoder side.

FIG. 16 shows an example of pre-processing technique for a horizontalsampling and side by side packing arrangement.

FIG. 17 and FIG. 18 show examples of pre-processing stages according tothe present disclosure.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

Embodiments of the present disclosure relate to image processing andvideo compression.

According to a first embodiment, a two-dimensional (2D) compatible orframe compatible three-dimensional (3D) video encoding system isprovided, comprising: a base layer, comprising a base layer videoencoder; at least one enhancement layer, associated with the base layer,the enhancement layer comprising an enhancement layer video encoder; andat least one pre-processing module, i) to pre-process the output of thebase layer video encoder and input the pre-processed output into theenhancement layer video encoder and/or ii) to pre-process the output ofone enhancement layer video encoder of one enhancement layer and inputthe pre-processed output into another enhancement layer video encoder ofanother enhancement layer.

According to a second embodiment, a two-dimensional (2D) compatible orframe compatible three-dimensional (3D) video decoding system isprovided, comprising: a base layer, comprising a base layer videodecoder; at least one enhancement layer, associated with the base layer,the enhancement layer comprising an enhancement layer video decoder; andat least one pre-processing module, i) to pre-process the output of thebase layer video decoder and input the pre-processed output into theenhancement layer video decoder and/or ii) to pre-process the output ofone enhancement layer video decoder of one enhancement layer and inputthe pre-processed output into another enhancement layer video decoder ofanother enhancement layer.

According to a third embodiment, a two-dimensional (2D) compatible orframe compatible three-dimensional (3D) video system is provided,comprising: a base layer, comprising a base layer video encoder and abase layer video decoder; at least one enhancement layer, associatedwith the base layer, the enhancement layer comprising an enhancementlayer video encoder and an enhancement layer video decoder; at least oneencoder pre-processing module, i) to pre-process the output of the baselayer video encoder and input the pre-processed output into theenhancement layer video encoder and/or ii) to pre-process the output ofone enhancement layer video encoder of one enhancement layer and inputthe pre-processed output into another enhancement layer video encoder ofanother enhancement layer; and at least one decoder pre-processingmodule, i) to pre-process the output of the base layer video decoder andinput the pre-processed output into the enhancement layer video decoderand/or ii) to pre-process the output of one enhancement layer videodecoder of one enhancement layer and input the pre-processed output intoanother enhancement layer video decoder of another enhancement layer.

According to a fourth embodiment, a frame compatible three-dimensional(3D) video encoding system is provided, comprising: a base layer,comprising a base layer video encoder and a base layer multiplexer, thebase layer multiplexer receiving an input indicative of a plurality ofviews and forming a multiplexed output connected with the base layervideo encoder; and at least one enhancement layer, associated with thebase layer, the at least one enhancement layer comprising an enhancementlayer video encoder and an enhancement layer multiplexer, theenhancement layer multiplexer receiving an input indicative of theplurality of views and forming a multiplexed output connected with theenhancement layer video encoder, wherein the base layer video encoder isdirectly connected with the enhancement layer video encoder.

According to a fifth embodiment, a two-dimensional (2D) compatible orframe compatible three-dimensional (3D) video encoding method isprovided, comprising: base layer video encoding a plurality of images orframes; enhancement layer video encoding the plurality of images orframes; pre-processing base layer video encoded images or frames; andadopting the pre-processed base layer video encoded images or frame forthe enhancement layer video encoding.

According to a sixth embodiment, a two-dimensional (2D) compatible orframe compatible three-dimensional (3D) video decoding method isprovided, comprising: base layer video decoding a plurality of images orframes; pre-processing base layer video decoded images or frames;adopting the pre-processed base layer video decoded images or frames forenhancement layer video decoding; and enhancement layer video decodingthe plurality of images or frames;

According to a seventh embodiment, a two-dimensional (2D) compatible orframe compatible three-dimensional (3D) video method is provided,comprising: base layer video encoding a plurality of images or frames;enhancement layer video encoding the plurality of images or frames;pre-processing base layer video encoded images or frames; adopting thepre-processed base layer video encoded images or frame for theenhancement layer video encoding; base layer video decoding a pluralityof images or frames; pre-processing base layer video decoded images orframes; adopting the pre-processed base layer video decoded images orframes for enhancement layer video decoding; and enhancement layer videodecoding the plurality of images or frames;

According to an eighth embodiment, an encoder for encoding a videosignal according to the method of the fifth embodiment is provided.

According to a ninth embodiment, an apparatus for encoding a videosignal according to the method of the fifth embodiment is provided.

According to a tenth embodiment, a system for encoding a video signalaccording to the method of the fifth embodiment is provided.

According to an eleventh embodiment, a decoder for decoding a videosignal according to the method of the sixth embodiment is provided.

According to a twelfth embodiment, an apparatus for decoding a videosignal according to the method of the sixth embodiment is provided.

According to a thirteenth embodiment, a system for decoding a videosignal according to the method of the sixth embodiment is provided.

According to a fourteenth embodiment, a computer-readable mediumcontaining a set of instructions that causes a computer to perform themethod or methods recited above is provided.

Embodiments of the present disclosure will show techniques that enableframe compatible 3D video systems to achieve full resolution 3Ddelivery, without any of the drawbacks of the 2D compatible 3D deliverymethods (e.g., MVC). Furthermore, decoder complexity, in terms ofhardware cost, memory, and operations required will also be considered.Furthermore, improvements over the existing 2D compatible 3D deliverymethods are also shown.

1. 2D Compatible 3D Delivery

Applicants have observed that the MVC extension of the MPEG-4 AVC/H.264standard constrains prediction between the base and enhancement layers(see FIG. 9) to only utilize translational block based methods, whichalso include the optional consideration of illumination compensationmethods, i.e. weighted prediction.

This can severely affect coding performance since correlation betweenthe two layers is not fully exploited. In general, especially for thescenario of stereo, i.e. left and right view, coding, the two stereoviews are characterized more by an affine/geometric “motion”relationship due to the placement of the two cameras used to capture orgenerate (e.g., in the scenario of a computer generated 3D videosequence) the 3D content, which cannot be captured well usingtranslational (vertical and horizontal only) motion compensationmechanisms. This is also true for the multiview case, where more thantwo views for a scene are available. Reference is made to the exampleshown in FIG. 10.

The content may also have differences in focus or illumination becauseof the camera characteristics, which again make prediction lessaccurate. Furthermore, the MVC specification only accounts for 2Dcompatible 3D video coding systems and has no provision for framecompatible arrangements such as those shown in FIG. 7 of the presentapplication.

To provide a solution to the first problem, i.e. inaccurate predictionfrom the base to the enhancement layer, a pre-processing stage isintroduced between the base and enhancement layer encoders and decodersin accordance with an embodiment of the present disclosure to process orrefine the first encoded view for prediction before encoding the secondview. In particular, in accordance with such embodiment, data from thebase layer are pre-processed and altered using some additionalparameters that have been signaled in the bitstream. The pictures thusgenerated can be available for prediction, if desired. Such process canbe used globally or regionally and is not limited to a block-basedprocess.

Reference can be made, for example to FIG. 12, where a 3D pre-processor(1210) is shown on the encoding side between base layer video encoder(1220) and enhancement layer video encoder (1230), and a3D-pre-processor (1240) is shown on the decoding side between base layervideo decoder (1250) and enhancement layer video decoder (1260).

The role of this pre-processing stage is to process and adjust thecharacteristics of the base layer video to better match those of theenhancement layer video. This can be done, for example, by consideringpre-processing mechanisms such as filtering (e.g., a sharpening or a lowpass filter) or even other more sophisticated methods such asglobal/region motion compensation/texture mapping.

These methods require the derivation of parameters appropriate for eachof them, such as i) the filters, ii) the filter coefficients/length thatshould be used, and/or iii) the global motion compensation correctionparameters that should be applied to the image to generate the newprediction.

A set of parameters could be derived for the entire video, scene, orimage. However, multiple parameters could also be used within an image.Parameters, in this scenario, could be assigned for different regions ofan image. The number, shape, and size of the regions could be fixed orcould also be adaptive. Adaptive regions could be derived givenpre-analysis of the content (e.g., a segmentation method), and/or couldbe user-specified, in which case signaling of the characteristics of theregions (e.g., shape and size) can be signaled within the bitstream.

As an example, a system may signal that each frame is split in N×Mrectangular regions, or could signal explicitly the shape of each regionusing a map description. Determination and signaling of such informationcould follow the description presented in U.S. Provisional Application61/170,995 filed on Apr. 20, 2009, for “Directed Interpolation and DataPost-Processing”, which is incorporated herein by reference in itsentirety.

According to one embodiment, an encoder can evaluate all or a subset ofpossible pre-processing methods that could be used by the system, bycomparing the output of each method compared to the predicted signal(enhancement layer). The method resulting in best performance, e.g. bestin terms of complexity, quality, resulting coding efficiency, amongothers, or a combination of all of these parameters using methods suchas Lagrangian optimization, can be selected at the encoder. Referencecan be made, for example to FIGS. 3 to 5 of the above mentioned U.S.Provisional 61/170,995, incorporated herein by reference in itsentirety.

According to another embodiment, multiple parameters that correspond tothe same region in the image could also be signaled to generate multipledifferent potential predictions for the enhancement layer. Reference canbe made, for example, to FIG. 17 and FIG. 18 of the present disclosure.FIG. 17 shows a pre-processing system with N filterconsideration/signaling. Multiple filters can be selected for a singleregion by selecting the M best filters that provide the best desiredperformance which can be defined as quality, cost, enhancement layercoding performance, etc. FIG. 18 shows pre-processing withmulti-parameter consideration.

Similarly to MVC, where the base layer is added in the reference bufferof the enhancement layer for prediction purposes (see FIG. 9), the newprocessed images, e.g., after filtering or global motion compensationcorrection, are also added in the reference buffer of the enhancementlayer, as shown in FIG. 13, where the output of pre-processor (1310) isconnected to the reference buffer (1320) of the enhancement layer.According to some embodiments of the present disclosure, the referencebuffer (1320) may already include other references such as previouslyencoded and decoded pictures from the enhancement layer or even picturesgenerated from processing previously encoded and decoded base layerpictures.

As noted above, for every previously decoded base layer picture, one ormore new processed reference pictures can be generated and added in theenhancement layer buffer (1330) as additional reference pictures. All ofthese references could be considered for prediction using motioncompensation methods and mechanisms such as the reference indexconcept/signaling that is available within codecs such as MPEG-4 AVC(Advanced Video Coding). For example, assuming that a base layer picturehas been processed to generate two different reference pictureinstances, ref_(b0) and ref_(b1), and also ref_(e), which corresponds tothe previously encoded enhancement layer picture, is available as areference, one can assign reference indices (ref_idx) 0, 1, and 2 tothese pictures respectively. If a macroblock in the current enhancementlayer picture selects ref_(b0) then ref_idx=0 is signaled in thebitstream. Similarly, ref_idx 1 or 2 are signaled for MBs selectingref_(b1) and ref_(e) respectively.

The availability of such processed reference pictures in the enhancementlayer buffer involves the consideration of i) appropriate memorymanagement and ii) reference ordering operations in both the encoder andthe decoder as is also done in MPEG-4 AVC and its SVC and MVCextensions.

Memory management operations take into consideration which referencesare removed or added in the reference buffer for prediction, whilereference ordering takes into consideration the order of how referencesare considered for motion compensation, which itself affects the numberof bits that will be used when signaling that reference.

Default memory management and reference ordering operations could beconsidered based on the systems expectation of which is likely to be theleast useful (for memory management) or most correlated reference (forreference ordering). As an example, a first-in first-out (FIFO) approachcould be considered for memory management, while also both base andenhancement layer pictures corresponding to the same time instance areremoved at the same time. On the other hand, base layer information fromprevious pictures need not be retained after it was used, thereforesaving memory. Alternative or additional memory management techniquescan include adaptive memory management control.

Similarly, for default ordering, the base layer reference thatcorresponds to the current time as the current enhancement layer to beencoded could be placed in the beginning of the reference list forprediction, while the rest of the references can be ordered according totemporal distance, coding order, and/or layer relationships. Forexample, and assuming a single processed reference from the base layer,a default reference order can be as follows:

-   -   a) place processed base layer reference, if available, as first        reference in list (ref_idx=0)    -   b) proceed with alternating order and add enhancement layer and        previously processed base layer reference pictures in reference        buffer according to their temporal distance. If two pictures        have the same temporal direction, then determine order according        to direction of reference (past or future compared to current        picture). If picture/slice type allows one list, then past        pictures take precedence over future, while if picture/slice        type allows two lists, then for the first list past pictures        take precedence over future, while for the second list future        pictures take precedence over past.        When multiple references from the base layer are available the        default order can also be affected, for example, by the order        these references are specified in the bitstream.

The above rules could be specified by the system. The person skilled inthe art will also understand that such operations can apply to multiplereference lists, such as in the case of the two prediction listsavailable in B slices of MPEG-4 AVC/H.264. Explicit memory managementand reference ordering operations could also be utilized, which allowfurther flexibility to be added to the system, since the system canselect a different mechanism for handling references for an instance,given reasons such as coding performance and error resiliency amongothers. In particular, alternatively or in addition to a defaultordering, users may wish to specify their own ordering mechanism and usereordering instructions that are signaled in the bitstream, similarly towhat is available already in MPEG-4 AVC, that specify exactly how eachreference is placed in each reference list.

2. Frame Compatible 3D Delivery

The above approach can be extended to frame compatible 3D delivery,generally shown in FIG. 7 of the present application. In this scenario,instead of having a base layer that corresponds to a single view, thebase layer now corresponds to two views that have been previouslysubsampled using a variety of methods and multiplexed using a variety ofarrangements. As mentioned earlier, subsampling could includehorizontal, vertical, or quincunx among others, and multiplexing couldinclude side by side, over-under, line or column interleaved, andcheckerboard among others.

Reference can be made, for example, to the embodiment of FIG. 11, wherea base layer 3D multiplexer (1110) connected with a base layer videoencoder (1120) and an enhancement layer 3D multiplexer (1130) connectedwith an enhancement layer video encoder (1140) are shown.

In this scenario, instead of missing information for one of the twoviews, what are essentially missing are resolution and/or high frequencyinformation for both views. Therefore, what is desired by such system isthe ability, if desired, to add back the missing information to thesignal.

In the simplest embodiment of such a system, subsampling can beperformed using basic pixel decimation (1111), (1112), (1131), (1132),i.e. without necessarily the consideration of any filtering, where thebase layer corresponds to one set of pixels in the image and theenhancement layer corresponds to another set without filtering.

For example, for the horizontal sampling+side by side arrangement, theleft view samples in the base layer correspond to the even samples inthe original left view frame, the right view samples in the base layercorrespond to the odd samples in the original right view frame, whilethe left and right view samples in the enhancement layer correspond tothe remaining, i.e. odd and even samples, in their original framesrespectively.

In this scenario, very high correlation exists between the base andenhancement layers which cannot be exploited as efficiently using theprediction methods provided by MVC.

Similarly to what previously done for the 2D compatible systemembodiments, a pre-processing stage (1150) is introduced that processesthe base layer information, before utilizing this information as apotential prediction for the enhancement layer.

A further embodiment of the present disclosure provides for a framecompatible 3D architecture similar to the one shown in FIG. 11, withframe compatible signals but without 3D pre-processors (or with3D-processors operating in a “pass-through mode”) and with the presenceof data multiplexing at the input (1110), (1130) and data remultiplexingat the output (1170), (1180).

More specifically, apart from filtering and global motion compensationcorrection that were discussed in the previous section, fixed oradaptive interpolation techniques that account for the characteristicsof the sampling and arrangement methods used by the content, can beutilized to process the base layer.

For example, processing could include separable or non-separableinterpolation filters, edge adaptive interpolation techniques, filtersbased on wavelet, bandlet, or ridgelet methods, and inpainting amongothers.

Other methods that try to enhance resolution or can help with predictingmissing frequency information could also be used. Methods that considerinformation from both views, such as copying the data from the baselayer right view to predict the enhancement layer left view, can also beused. Similarly to what discussed above, these methods could be againapplied at the sequence, scene, image, or/and region level, whilemultiple such parameters could be signaled to allow the generation ofmultiple potential references for prediction. Regions, as in the case ofthe 2D compatible system, can be predefined or signaled within abitstream.

It should be noted that it is not necessary for the enhancement layer toutilize the entire or even any part of a prediction/reference picture.In other words, the enhancement layer encoder (1140) can consider theprocessed images from the base layer for prediction, but only ifdesired. For example, the user may select to predict the entireenhancement layer from a previously decoded enhancement layer picture,or if multiple pre-processed base layer pictures are available, theencoder can select only one of them (e.g. in view of a rate distortioncriterion) or any combination of two reference pictures, assuming thepresence of a bi-predictive coding. The same can also occur at theregion level.

For example, the entire or part of the top half of a base layerprocessed image was used to predict the current enhancement layerpicture, but instead for the bottom part the encoder selected to useagain a previous enhancement layer picture. Additional, block (e.g. forMPEG-2 or MPEG-4 AVC like codecs) or other local motion compensationmethods (e.g. a motion compensated method utilized by a future codec)could be used as part of the enhancement layer codec, which maydetermine that a different prediction, e.g. temporal, may provide betterperformance.

However, such prediction samples could also be combined together in abi-predictive or even a multi-hypothesis motion compensated frameworkagain at the block or region level, resulting in further improvedprediction.

It should be apparent, similarly to how references are processed in MVC,that each reference in the systems and methods according to the presentdisclosure could be further interpolated (e.g., using the MPEG-4AVC/H.264 interpolation filters) and utilized with reference re-orderingand weighted prediction when used for prediction.

FIG. 14 and FIG. 15 show in detail the pre-processing module (1410) onthe encoder side and the pre-processing module (1510) on the decoderside.

The design and selection of the pre-processing method can be part of anencoder and can be based on user input or other criteria such as cost,complexity, and coding/quality performance

An example of such process is shown in FIG. 16. After a predictionreference from the base layer is created, as stated above, thisreference (1610) and all other references (1620) (e.g. previously codedpictures from the enhancement layer or past or differently processedprediction references from the base layer) are considered within amotion compensated architecture to refine the prediction (1630) of theenhancement layer at a lower level, e.g. block or region.

While the process according to the present disclosure is similar to howMPEG-4 AVC/H.264 and its MVC and SVC extensions also perform prediction,better references are used herein in view of the presence of apre-processing stage. After such prediction is performed, the residualfor the enhancement layer can be computed, transformed, quantized andencoded, with any additional overhead such as motion information, usingmethods similar to those used in the MPEG-4 AVC codec.

Other methods or future codecs can also be utilized to encode suchinformation. This residual can be dequantized, inversed transformed andthen added back to the prediction to reconstruct the enhancement layersignal.

According to a further embodiment of the present disclosure, optionalin-loop filtering (as shown in FIG. 14 and FIG. 15), such as deblocking,that applies only on the enhancement layer could be used to reduceartifacts, such as blockiness. It should be noted that the enhancementlayer in this scenario is in a similar packing arrangement as that ofthe base layer. For display purposes, the base and enhancement layerdata would need to be re-multiplexed together as to generate twoseparate, full resolution, left and right images. Re-multiplexing couldbe done by using simple interleaving of the base and enhancement layers.As shown in FIG. 11, re-multiplexing of the base and enhancement layerdata occurs through multiplexers (1170) and (1180).

In an alternative embodiment, the base layer information is alsofiltered prior to combining it, e.g. replacing half of the samples oraveraging half of the samples, with the samples from the enhancementlayer. Reference can be made to filters G_(L) ^(B2) and G_(L) ^(E) ofFIG. 11, where G_(L) ^(B2) can be averaged with G_(L) ^(E) in suchalternative embodiment.

In a different embodiment, generation of the base layer video couldoccur through the use of filtering (e.g., to reduce aliasing) prior todecimation. In this scenario, and excluding compression impact, a singlelayer approach may not be able to generate a true full resolution image.Such single layer can, however, help reconstruction of some of the lostfrequencies or accurate reconstruction of half of the resolution of theoriginal signal.

To alleviate for this problem, an additional, 3rd layer can beintroduced that tries to correct for any errors introduced by the priorfiltering in the base layer. Reference can be made to layer (1160) ofFIG. 11. Similar methods could be used for predicting the signal in thisnew layer from data in both the base and enhancement layers. The personskilled in the art will understand that data from the base layer couldbe good enough predictors for this new layer without processing or withvery little processing.

However, it is possible that the enhancement layer may be of higherquality and could provide additional information that could be alsoutilized for the prediction of this layer. Therefore, in the presentdisclosure, apart from prediction references coming from the base layerand previously reconstructed references from this third (secondenhancement) layer, references generated using pre-processing of thesecond (first enhancement) layer, or references using pre-processingwhile considering both base and first enhancement layer could be used.Therefore, embodiments of the present disclosure can be provided wherethere is more than one pre-processing stage on the encoding side andmore than one pre-processing stage on the decoding side.

In an example, the prediction reference could be generated using edgeadaptive interpolation of the enhancement layer while the edge adaptivedecisions could be based also on the edges and samples of the baselayer. Weighted averaging of an interpolated enhancement layer and theoriginal or filtered base layer could generate a different prediction.Other mechanisms to generate a prediction picture for this enhancementlayer could also be used, as discussed above, also including methodsemploying wavelet interpolation, inpainting and others.

Therefore, according to the teachings of the present disclosure,delivery of 3D content is extended using frame compatible methods, i.e.Checkerboard video delivery, side by side, over-under, etc., to supportfull resolution through the introduction of additional enhancementlayers. These additional enhancement layers can provide apart fromadditional resolution and/or quality, additional functionalities such asimproved streaming and complexity scalability.

The teachings provided in the present disclosure can also be seen asextensions of existing scalable video coding technologies such as theScalable Video Coding (SVC) and Multiview Video Coding (MVC) extensionsof the MPEG-4 AVC standard, however, with the consideration of improvedmethods for predicting from one layer to the next.

This advantage can result in improvements in coding efficiency, whilehaving similar, and in some cases reduced complexity compared to thesetechnologies. Although some embodiments can be based on the MPEG-4AVC/H.264 video coding standard, the techniques presented in the presentdisclosure are codec agnostic and other video coding standards andcodecs such as MPEG-2 and VC-1 can be applied to them.

Possible applications of the teachings of the present disclosure arestereoscopic (3D) format video encoders and decoders that can beapplied, by way of example and not of limitation, to Blu-ray videodiscs, broadcast and download/on demand systems, satellite systems, IPTVsystems, and mobile devices that support 3D video.

The methods and systems described in the present disclosure may beimplemented in hardware, software, firmware or combination thereof.Features described as blocks, modules or components may be implementedtogether (e.g., in a logic device such as an integrated logic device) orseparately (e.g., as separate connected logic devices). The softwareportion of the methods of the present disclosure may comprise acomputer-readable medium which comprises instructions that, whenexecuted, perform, at least in part, the described methods. Thecomputer-readable medium may comprise, for example, a random accessmemory (RAM) and/or a read-only memory (ROM). The instructions may beexecuted by a processor (e.g., a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), or a field programmablelogic array (FPGA)).

The examples set forth above are provided to give those of ordinaryskill in the art a complete disclosure and description of how to makeand use the embodiments of the encoding and decoding architectures forformat compatible 3D video delivery of the disclosure, and are notintended to limit the scope of what the inventors regard as theirdisclosure. Modifications of the above-described modes for carrying outthe disclosure may be used by persons of skill in the video art, and areintended to be within the scope of the following claims. All patents andpublications mentioned in the specification may be indicative of thelevels of skill of those skilled in the art to which the disclosurepertains. All references cited in this disclosure are incorporated byreference to the same extent as if each reference had been incorporatedby reference in its entirety individually.

It is to be understood that the disclosure is not limited to particularmethods or systems, which can, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting. As used in this specification and the appended claims, thesingular forms “a,” “an,” and “the” include plural referents unless thecontent clearly dictates otherwise. The term “plurality” includes two ormore referents unless the content clearly dictates otherwise. Unlessdefined otherwise, all technical and scientific terms used herein havethe same meaning as commonly understood by one of ordinary skill in theart to which the disclosure pertains.

A number of embodiments of the disclosure have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the presentdisclosure. Accordingly, other embodiments are within the scope of thefollowing claims.

What is claimed is:
 1. A decoder for decoding a frame compatiblethree-dimensional (3D) video signal, the decoder comprising: an input toreceive a coded bitstream comprising encoded images or pictures, eachimage comprising two views, wherein the two views are interleaved in acheckerboard pattern; one or more processors with memory to perform: afirst decoding function for generating a base layer of reconstructedimages based on the coded bitstream; a first storage function forstoring in a base layer decoding reference buffer the base layerreconstructed images; a first pre-processing function for pre-processingthe base layer reconstructed images to generate first pre-processedimages; a second storage function for storing, in a first enhancementlayer decoding reference buffer, the first pre-processed images for afirst enhancement layer video decoding; and a second decoding functionfor generating a first enhancement layer of reconstructed images basedon the coded bitstream and the first pre-processed images, wherein thetwo views are decoded and processed in each of the base layer and thefirst enhancement layer.
 2. The method of claim 1, wherein the one ormore processors further decompose a checkerboard interleaved image intoan upconverted first view image and an upconverted second view image. 3.The method of claim 1, wherein the one or more processors furtherperform: a second pre-processing function for pre-processing the firstenhancement layer of reconstructed images to generate secondpre-processed images; a third storage function for storing in a secondenhancement layer decoding reference buffer the second pre-processedimages for a second enhancement layer video decoding; and a thirddecoding function for generating a second enhancement layer ofreconstructed images based on the coded bitstream and the secondpre-processed images.